For casual/personal travel, I wear flip flops, shorts and polo shirts - whatever I think won't set off the metal detector and will allow me to seamlessly zip through security. No shoes to untie, no jacket to take off, no laptop, etc.

For work travel, I have to go in suits 90% of the time, so that's a little tougher. Dress shoes that have to be untied and re-tied, laptop, etc.